cgimageref

I'm generating a bunch of tiles for CATiledLayer . It takes about 11 seconds to generate 120 tiles at 256 x 256 with 4 levels of detail on an iPhone 4S. The image itself fits within 2048 x 2048. My bottleneck is UIImagePNGRepresentation . It takes about 0.10-0.15 seconds to generate every 256 x 256 image. I've tried generating multiple tiles on different background queue's, but this only cuts it down to about 9-10 seconds. I've also tried using the ImageIO framework with code like this: - (void)writeCGImage:(CGImageRef)image toURL:(NSURL*)url andOptions:(CFDictionaryRef) options {

I'm building an Iphone app that needs to convert a UIImage to a CGImageRef. I have no idea how to do this and would love some help. I have no background in working with images... :) It is as simple as image.CGImage where image is a UIImage object. CGImageRef cgImage = [someImage CGImage]; Satish Azad write folowing to get CGImage from UIImage: Suppose u have an UIImage object ex imageObject then, CGImage imageRef = imageObject.CGImage 来源： https://stackoverflow.com/questions/6067307/uiimage-cgimageref

while working with OpenCV I need to convert a NSImage to an OpenCV multi-channel 2D matrix (cvMat) and vice versa. What's the best way to do it? Greets, Dom dom Here's my outcome, which works pretty well. NSImage+OpenCV.h: // // NSImage+OpenCV.h // #import <AppKit/AppKit.h> @interface NSImage (NSImage_OpenCV) { } +(NSImage*)imageWithCVMat:(const cv::Mat&)cvMat; -(id)initWithCVMat:(const cv::Mat&)cvMat; @property(nonatomic, readonly) cv::Mat CVMat; @property(nonatomic, readonly) cv::Mat CVGrayscaleMat; @end NSImage+OpenCV.mm: // // NSImage+OpenCV.mm // #import "NSImage+OpenCV.h" static void

I am writing this method to calculate the average R,G,B values of an image. The following method takes a UIImage as an input and returns an array containing the R,G,B values of the input image. I have one question though: How/Where do I properly release the CGImageRef? -(NSArray *)getAverageRGBValuesFromImage:(UIImage *)image { CGImageRef rawImageRef = [image CGImage]; //This function returns the raw pixel values const UInt8 *rawPixelData = CFDataGetBytePtr(CGDataProviderCopyData(CGImageGetDataProvider(rawImageRef))); NSUInteger imageHeight = CGImageGetHeight(rawImageRef); NSUInteger